Ex parte Agarwal

Board of Patent Appeals and Interferences

Feb 16, 2000

08305262 (B.P.A.I. Feb. 16, 2000)

1
THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered today (1)
was not written for publication in a law journal and (2) is
not binding precedent of the Board.
Paper No.12
UNITED STATES PATENT AND TRADEMARK OFFICE
__________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________
Ex parte ROHIT AGARWAL
__________
Appeal No. 1997-0401
Application 08/305,262
___________
ON BRIEF
___________
Before THOMAS, HAIRSTON and FRAHM, Administrative Patent
Judges.
FRAHM, Administrative Patent Judge.
DECISION ON APPEAL
Appellant has appealed to the Board from the examiners’
final rejection of claims 1 to 20, which constitute all of the
pending claims in the application before us on appeal.
BACKGROUND
The subject matter on appeal is directed to a method for
dithering during a color conversion process in a digital video
Appeal No. 1997-0401
Application 08/305,262
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processing system such that video artifacts (i.e., graininess)
can be reduced (see specification, pages 1 to 2; Brief, page
3). Appellant recognized that conventional dithering
processes which are known to reduce contouring in images
suffer from the use of a fixed dithering matrix, resulting in
undesirable artifacts, or graininess, being reproduced in an
image (see specification, page 2). As indicated by appellant
(specification, pages 2 to 3; Brief, page 3), when the
dithering matrix added to groups of pixels in an image is
changed frame by frame in a sequence of frames of pixels, it
is possible to reproduce a more natural appearing image and to
prevent graininess normally associated with dithering.
Appellant’s dithering method recited in claims 1 to 20 on
appeal provides that different dithering matrices be picked
over time such that the time-averaged dither intensity at any
given pixel location is zero (specification, page 3). Thus,
by using different dither matrices frame by frame sequentially
in time in patterns that average out to a zero dither
intensity for each pixel location, both graininess and
contouring in an image can be eliminated (see specification,
page 6). As further discussed, infra, we find that the
Appeal No. 1997-0401
Application 08/305,262
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applied references to Oz, and particularly Keith, fail to
teach or suggest at least this
important feature of adding different dither value matrices to
pixels "wherein the time-averaged value of said dither values
at a given pixel location is zero" (independent claim 1 on
appeal).
Representative method claim 1 is reproduced below:
1. In a digital video processing system, a method for
dithering quantized color values having a given step size
during a color conversion process, comprising the steps of:
(A) adding a set of dither values to first color values
throughout a first frame of digital video values;
(B) adding a different set of dither values to
second color values throughout a second frame of digital video
values, said second frame being subsequent to said first frame
in time sequence; and,
(C) repeating steps (A) and (B) for subsequent
frames in time order;
wherein the time-averaged value of said dither
values at a given pixel location is zero.
The following references are relied on by the examiners:
Keith 5,381,180 Jan. 10,
1995
(filed Aug. 16,
1993)
Oz 5,450,098 Sep. 12,
Appeal No. 1997-0401
Application 08/305,262
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1995
(filed Sep. 19,
1992)
Claims 1 to 20 stand rejected under 35 U.S.C. § 103. As
evidence of obviousness, the examiner relies upon Oz in view
of Keith.
Rather than repeat the positions of appellant and the
examiner, reference is made to the Brief and the Answer for
the respective details thereof.
OPINION
For the reasons generally set forth by appellant in the
Brief, and for the reasons which follow, we will reverse the
rejection of claims 1 to 20 under 35 U.S.C. § 103. In
reaching our conclusion on the issues raised in this appeal,
we have carefully considered appellant’s specification and
claims, the applied patents, and the respective viewpoints of
appellant and the examiner. As a consequence of our review,
we are in general agreement with appellant that the applied
references would neither have taught nor suggested the
appellant’s claims on appeal.
The examiner and appellants are in agreement that the
primary reference to Oz does not teach dithering. The
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Application 08/305,262
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examiner relies upon the secondary reference to Keith to teach
or suggest a dithering process used to prevent contouring in
an image. We agree with appellant that the primary issue
before us on appeal "is whether Keith discloses or suggests a
dithering method or apparatus which applies a different
dithering matrix (dithering values) to identically located
groups of pixel values over sequential frames of digital
video" (Brief, page 5). We are in agreement with appellant
(Brief, pages 5 to 7) that Keith fails to teach or suggest the
recited feature of representative claim 1
of applying different dithering values to pixels in sequential
frames such that the time-averaged value of the dither values
at a given pixel location is zero.
Appellant argues (Brief, page 5) that Keith fails to
teach or suggest applying different dithering matrices to a
sequence of digital video frames over time, as is done in
claim 1 on appeal. We agree, and we find that this zero time-
averaging dithering feature is neither taught nor would have
been suggested by Keith. Although we agree with the examiner
that Keith teaches adding random noise in the form of a dither
matrix to each of three-component data, we find that Keith
Appeal No. 1997-0401
Application 08/305,262
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fails to fairly teach or suggest that the random noise used to
produce dithered images changes over time. Thus, we are also
in agreement with appellant (Brief, page 6) that Keith fails
to teach or suggest that different noise values be applied to
pixels in subsequent frames as required by representative
claim 1 on appeal.
We agree with appellant that "Keith expressly discloses
generating a single set of dithering matrices (one for each of
the U and V components)" (Brief, page 6), as opposed to using
differing dithering matrices over time as in the claims on
appeal. In Keith, each component is processed using the same
dithering matrix over and over. There is no disclosure of
using different matrices over time for a group of pixels in an
image. Our review of Keith reveals that "[t]his processing is
performed for each (4X4) subimage of each video image in the
sequence of video images" (Keith, column 4, lines 16 to
19)(emphasis added). Therefore, we cannot agree with the
examiner (Answer, pages 3 to 4) that one of ordinary skill in
the art looking at Keith (especially column 2, lines 49 to 55
as noted by the examiner) would have been motivated to use
differing dithering matrices over time in order to time-
Appeal No. 1997-0401
Application 08/305,262
7
average pixel values to zero.
Accordingly, we cannot sustain the rejection of claims 1
to 20 under 35 U.S.C. § 103.
Although we find that the examiner has made a prima facie
case of obviousness as to the appealed claims, we conclude
that appellant has rebutted this prima facie case by
successfully showing that the specific zero time-averaging
dithering method of the appealed claims is neither taught nor
would have been fairly suggested by the secondary reference to
Keith. In view of the foregoing, the decision of the examiner
rejecting claims 1 to 20 under 35 U.S.C. § 103 is reversed.
CONCLUSION
The decision of the examiner rejecting claims 1 to 20
under 35 U.S.C. § 103 over Oz in view of Keith is reversed.
REVERSED

Appeal No. 1997-0401
Application 08/305,262
8
JAMES D. THOMAS )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
KENNETH W. HAIRSTON )
Administrative Patent Judge ) APPEALS AND
)
) INTERFERENCES
)
ERIC FRAHM )
Administrative Patent Judge )
EF/pgg
William H. Murray
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